Need help with Video card drivers.

I have just dowloaded Soldat on my new computer but it wont work. It keeps coming up with "Could not initialize DirectX Graphics. You must have installed DirectX 8 or better. Try running Soldat in compatibility mode."

I don't get it because i have DirectX 9.0c and tried it in compatibility mode but nothing works . A friend told me to update my video drivers but i don't know how to. Please help TechSpot?